Slavery was not the issue. Absent slavery would you still oppose the South seceding? How about the colonists seceding from Great Britain? How about Ukraine from Soviet Union?
"“When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.”
Based on your comments I would say your sympathies were with the confederacy. Apologies if I'm wrong.
Slavery was not the issue.
According to the confederacy's own statements giving the reason for seceding, it was.
Absent slavery would you still oppose the South seceding?
As long as we are the United States, yes. Read into that what you will.
How about the colonists seceding from Great Britain?
No, I would not have opposed seceding to escape how the king was exploiting his own citizens. That is not the same thing as seceding to preserve slavery.
How about Ukraine from Soviet Union?
Do you equate the breakup of the Soviet Empire with seceding to preserve slavery? If anything, it was the exact opposite.